Growing Evergreens in Containers All Year

At this time of year many of our customers decide to plant an evergreen in their urns, whiskey barrels, and larger outdoor containers. “What evergreen will live through the winter outside?” they ask. Here’s the general guideline, and a couple of shrub suggestions that are particularly good on Cape Cod.

• No matter where you live, the general rule of thumb is that for a plant to live in a container over the winter it should be hardier two zones colder than where you live. So here on Cape Cod, where most of us are in a warm zone 6 bordering on a cold zone 7, all zone 4 shrubs will be fine and many zone 5 plants will live as well. This USDA hardiness zone guideline works because the soil in containers usually gets about 20 degrees colder than ground temperatures.
• Dwarf Alberta Spruce are the favorite evergreen for containers. They are slow growing, extremely hardy, and grow well in part shade to full sun.
• Dwarf white pine shrubs also do well in containers. ‘Minuta,’ ‘Soft Touch,’ and ‘Blue Jay’ are three common varieties that are rounded in shape. Grow these in part-shade to full sun.
• Hinoki false cypress are very attractive and hardy evergreens. These shrubs come in a variety of foliage textures and colors, and are often more asymmetrical than other evergreens so they appeal to people who like a more natural, wind-swept look. Hinoki false cypress are extremely wind tolerant.
• Here on the Cape blue hollies such as ‘Blue Princess’ and ‘Blue Maid’ do well in large containers. These are larger growing plants over time, however, so you might plan on placing the holly in the landscape after a year or two. In the coldest of winters blue holly can suffer from wind burn as well, so plan on using these lovely plants in more sheltered locations.